1. Field of the Invention
This invention is concerned with a caliper gauge defined by a main scale and a slider sliding by contacting the main scale.
2. Description of the Related Art
Several caliper gauges have previously been used, for example, a vernier type caliper gauge defined by a main scale having thereon a longitudinal graduation and a slider slidingly contacting the main scale and having thereon vernier graduation, a dial display type caliper gauge provided for displaying a measured length by converting a displacement value of a slider into a corresponding rotation of an indicator related to the slider, and a digital display type caliper gauge by converting a displacement value of a slider into an electrical signal by means of an encoder such as a photo-type, a capacitance-type or a magnetic-type encoder to indicate a measured length digitally on a digital display.
Using such conventional caliper gauge to measure an object, an operator generally keeps the object in one hand and holds the caliper gauge in the other hand to control a relative movement between the main scale and a corresponding slider with the thumb of the other hand urges and rotates a roller engageable with a main scale until a pair of inner jaws or outer jaws come into contact with a portion of the object to be measured. Accordingly, the objective length of the object can be known from a combination of the graduation on the main scale and the vernier graduation on the slider when using the vernier type caliper gauge, from the indicator when using the dial display type caliper gauge, or from the digital display when using the digital display type caliper gauge.
To move the slider contacting the main scale requires a bigger force than in instances involving a frictional resistance between the slider and the main scale. But, it is known from experience that a degree of the frictional resistance is changeable based upon the quality of the caliper gauge in a factory and upon the amount of deterioration over time. Furthermore, the operator is generally tending to move the slider quickly conduct a fast measure. Accordingly, there is a potential disadvantage such that the quick movement of the slider may damage the object to be measured when the jaws strike against the object.
Accordingly, when using the conventional caliper gauges, the operator is severely required to control the relative movement between the slider and the main scale to retain a measuring force. However, a sensitive and precise control through measurement by a person is rather difficult and causes a low working efficiency. Actually, the measuring force is unnecessarily big so as to strain the jaws and then cause a tolerance in the same under the Abbe principles. When the object is made of rubber, plastic or the like, errors because of a deformation of the object will be unavoidable.
As has been mentioned, any conventional caliper gauge should be held by one hand by its main scale to relatively move the slider in measurement, which causes the following disadvantages.
The main scale has a U-shaped section to move the slider, so that a holding of the main scale is not comfortable through measurement. More particularly, when the slider is close to the main scale for measurement, an area sufficient to hold the main scale is too limited.
Since the main scale is continuously held by hand, the main scale is then heated and may suffer therefrom. Especially in the digital display type caliper gauge, though electrodes are provided along the main scale there is a high probability that unacceptable damage will be done by heat.
Furthermore, in a factory, some operators will hold the caliper gauge by the main scale with a soiled hand. In this atmosphere, the graduation printed on the gauge will be too soiled to be read. When using the digital display type caliper gauge, if the operator's hand is soiled by chips, the electrodes provided in the caliper gauge will suffer therefrom.
An object of the present invention is to provide a caliper gauge which does not involve the above-mentioned disadvantages but can achieve a high working efficiency through measurement while retaining a comfortable measurement force in comfortable.
Another object of the present invention is to provide a caliper gauge which is comfortable in operation and reading the measured value with no suffering from the heat of the hand.